Although essential, the use of parenteral nutrition (PN) in pediatric populations with surgical gastrointestinal diseases, especially premature infants, is frequently associated with hepatic dysfunction that may ultimately result in transplantation and/or death. Studies suggest that soybean oil containing intravenous fat emulsions (IFE) may be a major contributing factor. Pilot data suggests that discontinuing soy based IFE and switching to a product comprised of omega-3 fatty acids (FAs) derived from fish oils may be effective in reversing preexisting PN associated liver disease through a combination of factors, including improved triglyceride clearance coupled with anti-inflammatory properties. The applicant believes that fish oil based emulsions, besides treating this fatal condition, could prevent it. This project plans to randomize in a double blind study 30 infants (<3 months) with gastrointestinal disease at the start of their PN course to receive PN with a fish oil based emulsion (15 patients) or a the standard of care soybean based emulsion (15 patients). Patients expected to be on PN at least 3 months will be enrolled over three years. To evaluate effectiveness of this alternative IFE, conventional biochemical tests of hepatic function will be assessed and compared between the two study populations. The primary outcome will be the proportion of children developing cholestasis over a three month period. In addition to preventing the development of liver disease, it is hoped that the children will continue to grow at the same rate or better than if they were receiving the standard fat emulsion. Other long term outcomes that will be evaluated include the frequency of inflammatory diseases including bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) that often occur in these critically ill infants. The ultimate goal of this project is to demonstrate that fish oil based emulsions can be approved by the FDA for use in children dependent on PN to while recovering from surgical gastrointestinal diseases. Use of PN with fish oil base emulsion may prevent liver dysfunction resulting generally in better heath outcomes for these children.